(a) Field of the Invention
The present invention relates to a device and method for transmitting a reference signal and, more particularly, to a device and method for transmitting a reference signal in a narrowband Internet of things (NB-IoT) system.
(b) Description of the Related Art
A wireless communication system has a minimum unit of time resource for data transmission. A long-term evolution (LTE) system defines a minimum unit of time resource as a transmission time interval (TTI). In the LTE system, a TTI corresponds to a length of two slots, and a length of one slot corresponds to a length of seven symbols.
Also, in a wireless communication system, a prearranged signal is transmitted between a transmitter and a receiver for channel estimation in the receiver. The LTE system defines a signal prearranged between the transmitter and the receiver for channel estimation of the receiver, as a reference signal (RS). In uplink, the RS includes a demodulation RS (DMRS) and a sounding RS (SRS). Such an RS, a minimum allocation unit of radio resource, has a fixed pattern. The LTE system defines a minimum allocation unit of radio resource as a resource block (RB), and the RB includes twelve subcarriers and seven symbols. In particular, in the LTE system, an uplink resource is allocated as an RB pair in one uplink subframe.
Meanwhile, in the NB-IoT system, uplink resource allocation permits dynamic scheduling in a subcarrier unit. Thus, the NB-IoT system requires a reference signal allocation method different from that of an existing LTE system.